在java正则表达式中组合白名单和黑名单 [英] Combine whitelist and blacklist in java regex expression

问题描述

我在构建正则表达式时遇到问题，该正则表达式允许使用除2个字符外的所有UTF-8字符：'_'和'？'

所以白名单是：^ [\\\000000-\\\ 00FFFF]
，黑名单是：^ [^ _％]

我需要将这些结合起来一个表达式。

我尝试了以下代码，但是没有按照我希望的方式工作：

  String input =this; 
模式p =模式
 .compile（^ [\\\-\\\FFFF] + $ | ^ [^ _％]）; 
 Matcher m = p.matcher（输入）; 
 boolean result = m.matches（）; 
 System.out.println（result）; 
  

输入：这个

实际输出：false

期望输出：true

解决方案

您可以使用

和 Java演示：

 字符串输入=这个; 
模式p = Pattern.compile（[\\\000000-\ uFFFF&& [^ _％]] +）; //没有锚点，因为使用`matches（）`
 Matcher m = p.matcher（输入）; 
 boolean result = m.matches（）; 
 System.out.println（result）; // => true 
  

I am having problems constructing a regex that will allow the full range of UTF-8 characters with the exception of 2 characters: '_' and '?'

So the whitelist is: ^[\u0000-\uFFFF] and the blacklist is: ^[^_%]

I need to combine these into one expression.

I have tried the following code, but does not work the way I had hoped:

    String input = "this";
    Pattern p = Pattern
            .compile("^[\u0000-\uFFFF]+$ | ^[^_%]");
    Matcher m = p.matcher(input);
    boolean result = m.matches();
    System.out.println(result);

input: this
actual output: false
desired output: true

解决方案

You can use character class intersections/subtractions in Java regex to restrict a "generic" character class.

The character class [a-z&&[^aeiuo]] matches a single letter that is not a vowel. In other words: it matches a single consonant.

Use

"^[\u0000-\uFFFF&&[^_%]]+$"

to match all the Unicode characters except _ and %.

More about character class intersections/subtractions available in Java regex, see The Java™ Tutorials: Character Classes.

A test at the OCPSoft Visual Regex Tester showing there is no match when a % is added to the string:

And the Java demo:

String input = "this";
Pattern p = Pattern.compile("[\u0000-\uFFFF&&[^_%]]+"); // No anchors because `matches()` is used
Matcher m = p.matcher(input);
boolean result = m.matches();
System.out.println(result); // => true

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